Something's - once again - brewing within the GNOME project. While a mere suggestion for now, and by no means any form of official policy, influential voices within the GNOME project are arguing that GNOME should become a full-fledged Linux-based operating system, and that the desktop environment should drop support for other operating systems such as Solaris and the BSDs. I have a feeling this isn't going to go down well with many of our readers.

Doesn't this mean that in order to run Gnome, one must use systemd?
What if people want to use sysvinit, initng, upstart, runit, or eINIT...?

I doubt most users care which init system they're running. The real question is what if most distros don't want to switch to using systemd, as it provides no real benefits over some of the other init systems out there and would require all packages' init scripts to be rewritten?
GNOME should go linux-only, imho, but it should not depend on systemd. Not everyone wants to reinvent the wheel like Poettering seems to enjoy doing. If he wants to integrate systemd support into GNOME, great. If the Ubuntu devs wish to integrate upstart support into GNOME, that's awesome. If Debian wants to integrate sysvinit support, more power to them. Forcing a hard dependency of systemd is probably one of the worst ideas I've heard... but, then again, most of GNOME 3 seems to be one huge bad idea. To those who think forcing systemd on everyone is a good idea, remember what happened when GNOME started depending on Pulseaudio and just how well that's turned out?